Six Sigma tools - T-Test
Two sample T-Test
- To compare two process. Find whether the two process is same, greater or smaller compare to standard based on 95% confident level. To confirm the process, below two observation are applied
- 1. Observed that the resulting p-value and α. Reject the null hypothesis, accept the alternative hypothesis.
- 2. Observed that the resulting p-value and α. Fail to reject the null hypothesis. we do not have evidence proving that Ho is true
- Basically there are two type of T-test which are two side T-test and one side T-test. However, One side T-test can be either left side T-test (smaller) or right side T-Test (greater).
- 1. Two side T-Test: Check on Process A = Process B
- Comparison Statement: Ho: μA=standard ; Ha: μA≠μB
- 1. Observed that the resulting p-value < α/2. Reject the null hypothesis, accept the alternative hypothesis.
- 2. Observed that the resulting p-value > α/2. Fail to reject the null hypothesis. we do not have evidence proving that Ho is true
- 2a. One side T-Test: Check on Process A ≥ Process B
- Comparison Statement: Ho: μA=standard ; Ha: μA < μB
- 2b. One side T-Test: Check on Process A ≤ Process B
- Comparison Statement: Ho: μA=standard ; Ha: μA > μB
- 1. Observed that the resulting p-value < α. Reject the null hypothesis, accept the alternative hypothesis.
- 2. Observed that the resulting p-value > α. Fail to reject the null hypothesis. we do not have evidence proving that Ho is true
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